1. Field of the Invention
The present disclosure relates to a vibration motor and a method of manufacturing the vibration motor.
2. Description of the Related Art
In recent years, for a silent notification device of mobile communication equipment and the like, or for other purposes, a vibration motor which makes a vibrator portion vibrate in a vertical direction by an interaction of a coil and a magnet which are disposed in a radial direction, has been in use. In the vibration motor disclosed in Japanese Patent Application Publication No. 2013-85438 and US Patent Application Publication No. 2012/0169150, two magnets are separately disposed in a vertical direction, such that their magnetic poles having the same polarity face each other. Accordingly, a vibration force of the vibration motor increases, when compared to a case in which a single magnet is used.
Meanwhile, in the magnet for a reciprocating motion device disclosed in Japanese Patent Application Publication No. 2004-320827, three or more poles in odd number are formed on a lateral surface of the magnet having a cylindrical shape. On the lateral surface of the magnet, an N-pole is provided to a longitudinal center portion, and an S-pole is provided to both end portions.